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Introducing ADO+

ADO+ is an evolutionary improvement to Microsoft® ActiveX® Data Objects (ADO) that provides platform interoperability and scalable data access. Because Extensible Markup Language (XML) is the format for transmitting data, any application that can read the XML format can process data. In the extreme case, the receiving component need not be an ADO+ component at all. It might be a Microsoft Visual Studio®-based solution or any application running on any platform.

Programmability

With Visual Studio development system version 7.0, you can program against your objects, not against tables and columns. ADO+ uses strongly typed programming in which business objects figure prominently.

For example, consider the following line of code, using conventional (not strongly typed) programming:

IF TotalCost > Table("Customer").Column("AvailableCredit") 

In this example, you are programming the ADO tables and columns.

With strongly typed programming, the same example is much easier:

IF TotalCost > Customer.AvailableCredit

Besides being easier to read, the strongly typed code is easier to write. Specifically, automatic statement completion is sensitive to the objects you are programming. In the following example, we are able to navigate across entities in our data set, and IntelliSense® technology shows the available tables related to Customers.

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Figure 1. Strongly Typed Programming with IntelliSense

Additionally typed data sets run faster at execution time because the application doesn't have to search through ADO collection objects each time it needs to access a data member.

Working with Data Sets

The centerpiece of any software solution using ADO+ is the data set. A data set is an in-memory copy of database data. A data set contains any number of data tables, each of which typically corresponds to a database table or view. A data set constitutes a "disconnected" view of the database data. That is, it exists in memory without an active connection to a database containing the corresponding tables or views.

At run time, data will be passed from the database to a middle-tier business object and then down to the user interface. To accommodate the exchange of data, ADO+ uses an XML-based persistence and transmission format. That is, to transmit data from one tier to another, an ADO+ solution expresses the in-memory data (the data set) as XML and then sends the XML to the other component.

The following illustration shows the major components of an ADO+ solution.

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Figure 2. ADO+ Architecture

To make working with data easy in Visual Studio 7.0, there are many new features. For the hardcore XML developer, Microsoft has included a rich color-coded XML Designer with statement completion and tag completion.

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Figure 3. Color-Coded XML Designer with Statement and Tag Completion

For a more graphic view of data, developers can use the design view of the XML Designer. Simply drag and drop tables from any data source, including Microsoft SQL Server™ and Oracle databases, from the Server Explorer to the design surface. You can create data sets that are made up of data from numerous sources including any XML file.

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Figure 4. ADO+ Data Set Designer

Often you need to add, modify, or delete data while you are designing your application. With the Data Preview tab, you can not only add and modify data, but also navigate the relationships of your data.

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Figure 5. Data Preview

The data-binding technologies for Visual Studio 7.0 have been dramatically improved to take full advantage of ADO+. So building user interfaces that interact with data is easy. More importantly, now you can bind values to business objects and Web Services.

Last Updated: 7/11/00  

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